Generally, a keypad of a phone is a unique interface apparatus that receives and transmits information from and to the other party during a call. A user presses buttons on the keypad to transmit a DTMF signal to the other party. The DTMF signal represents a total of 16 unit information, for example, digits 0 to 9, hook signals such as *, #, etc. Many operations, such as making a phone call to the other party, inputting a credit card number during a call, inputting a password, selecting menus using an automatic response system (ARS), etc are performed by combining the unit information.
All telephone terminals, including a general wire telephone terminal, an Internet phone terminal, and a mobile phone, include the keypad that transmits the DTMF signal or an apparatus similar to the keypad.
Meanwhile, the latest Internet phone terminal or the mobile phone includes a touch screen as a user interface apparatus therein from its own necessity.
Recently, a packet-based broadband converged network and a 3G mobile communication network are rapidly replacing the existing public switched telephone network (PSTN). An audio call and a video call can be made in the networks but the video call can be commonly used in near future.
The video call can perform the complicated works easier and more intuitively than the audio call by adding the vide channel to the audio channel and can perform the impossible works in the audio channel.
However, there is a limitation in performing the video call by the transmission and reception of the DTMF using the keypad when performing the complicated interaction with the other party.
Therefore, there is a need to transmit and receive the DTMF signal and the touch screen-related information during a call.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.